Dosimetrically customizable brachytherapy carriers and methods thereof in the treatment of tumors

ABSTRACT

Brachytherapy radioisotope carrier systems and methodology for providing real-time customized brachytherapy treatment to subjects with tumors difficult to control using conventional radiation therapy techniques. The invention generally relates to devices, methods and kits for providing customized radionuclide treatments, to help cure, slow progression or regrowth, or ameliorate the symptoms associated with tumors.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of priority under 35 U.S.C. §119(e)of U.S. Ser. No. 61/800,983, filed Mar. 15, 2013, the entire content ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to using radiation therapy to treattumors and more specifically to dosimetrically customizable carrierskits and techniques for using the invention in the treatment of tumors.

2. Background Information

Tumors in living organisms are highly variable in size, location andtheir amount of infiltration into normal tissues, the variability oftumors in general make them very difficult to treat with a one-size fitsall approach. Furthermore, the actual extent of tumors and/or void uponremoval are typically not known precisely until presented in theoperating room. Thus the options necessary to effectively treat a tumoror tumor bed need to be quite diverse.

Tumors are difficult to eradicate surgically as their infiltrativenature often precludes microscopically complete resection without unduemorbidity or mortality. This local persistence of tumor cells may becontrolled if sufficient radiation can be delivered safely prior toregrowth and replication of the residual tumor cells. Resective surgery,followed by radiation therapy in high doses, provides the best chancefor local control of a tumor. However, the ability to deliver high dosesof radiation in the post-operative setting is frequently limited byintolerance of surrounding healthy tissue. Radiation therapy is dividedinto external beam radiation therapy (EBRT) or teletherapy and internalradiation therapy or brachytherapy (BT). The therapeutic index is therelative amount of healthy tissue receiving high doses of radiationcompared to the dose delivered to the tumor or tumor bed. Improving thetherapeutic index may increase local control of tumors and/or decreasethe morbidity of treatment. The inherently localized nature of BT isrecognized as a technique to improve the therapeutic index in tumortreatment with radiation.

Brachytherapy involves placing a radiation source either into orimmediately adjacent to a tumor. It provides an effective treatment oftumors of many body sites. Brachytherapy, as a component ofmultimodality cancer care, provides cost-effective treatment.Brachytherapy may be intracavitary, as in gynecologic malignancies;intraluminal, as in but not limited to esophageal or lung cancers;external surface, as in but not limited to cancers of the skin, orinterstitial, as in but not limited to the treatment of various centralnervous system tumors as well as extracranial tumors of the head andneck, lung, soft tissue, gynecologic sites, rectum, liver, prostate, andpenis.

The currently available brachytherapy devices and techniques are lackingin the following areas: 1) the current carriers are unable to easilyaccommodate anatomically conformal and reproducible brachytherapy doses;2) do not facilitate real-time dosimetric customization for sparingnormal tissue, while delivering effective and safe doses of radiation totumors; and 3) are not able to incorporate additional therapeuticagents, including chemotherapy, and viral, targeted, and DNA damagerepair inhibitors.

The present invention addresses the deficiencies associated with currentbrachytherapy devices for treating highly variable tumors and tumoroperative beds and comprises of novel brachytherapy radioisotope carriersystems and methodology for providing real-time customized brachytherapytreatment to patients with difficult to control tumors and tumor sitesusing conventional radiation therapy techniques.

SUMMARY OF THE INVENTION

The present invention generally relates to devices, methods and kits forproviding a customized radionuclide treatment in a patient to help cure,slow progression or regrowth, or ameliorate symptoms associated withtumors. More specifically the embodiments described relate to aversatile dosimetrically customizable brachytherapy system for providinga targeted radiation dose to specific tissues on or within the humanbody using radionuclides in carriers.

An embodiment of the present invention comprises a radionuclide carriersystem comprising of one or more individual implantable carriersconfigured to hold radioactive seeds in a precise location relative to atreatment area in order to produce a dosimetrically customizable implantin real-time for an area to be treated and wherein the individualcarriers are small enough to fit in or on the area to be treated and thecarriers are selected from one or more circular or gamma dot carriersand/or star or arm-based carriers. Additional carrier system embodimentsmay feature only one or more dot carriers or one or more star orarm-based carriers for delivering the radionuclide dose to the tissue ofinterest.

Embodiments of the invention comprise a radionuclide carrier system thatis implantable and/or permanent (such as when used in the brain), whileother embodiments include carrier systems that are temporary and/ornot-implanted (such as when used to treat skin lesions and/or tumors).

An additional embodiment of a radionuclide carrier system is thecustomization and use of a real-time dosimetry based on precisedimensions and properties of the carriers to optimize the therapeuticindex for an affected area. With additional embodiments includingprecise dimensions and properties of the carriers by utilizinggelatin-based or collagen-based biocompatible materials of differingthicknesses below and/or above a radiation source to act as a spacer toachieve a desired radiation dose delivery and a sparing of normaltissue.

Further embodiments of the radionuclide carrier system, relate to theasymmetrical placement of the radionuclide (seed) in the carrier whichgives it additional inherent properties. In a normative location of thecarrier the radionuclide source or seed is offset away from the tumorbed side more than it is from the “normal” tissue side (for example, ina 4 mm thick carrier, the radionuclide seed is 3 mm off tumor and 1 mmoff “normal” tissue”). This may seem counterintuitive, but in practicethe reasons are that; a) the normal side is usually a void, and b) iftissues on the void remain nearby, additional spacing material (sheetsof collagen, cellulose, etc.) can be interposed. Additionally, thepresent invention also includes carrier systems which can be rapidlyadjusted in real-time wherein one wants a localized dose increase, suchas 1) a localized nodule of tumor remains just under one or morecarriers, 2) a critical structure exists near or under the implant, suchthat a localized area of relatively lessened dose is desired, 3) that animplant consisting of a few to several carriers uniformly spaced has aninherently less radioactive periphery and more intensely radioactivecenter due to the inverse square law (similar to a charcoal grill at theedges and at the center), or 4) the implant area is quite small, andjust a few carriers in the “normative” position would not deliver anadequate dose. In theses cases the embodied carrier system includesasymmetric source placement of carriers wherein in each case one or moreindividual carriers are reversed from the normative position (flipped)to solve the problem of hyper-local dose control. This is a 180 degreeflip. If the usual (normative) orientation is thicker side toward tumor,then flipped is RFNO (‘reversed from normative orientation’). Followingthe earlier example of a 4 mm thick carrier, the seed would be 3 mm offtumor and 1 mm off “normal” when in the normative location and 1 mm offtumor and 3 mm off “normal” when in the reversed from normativeorientation.

Another additional embodiment achieves the real-time proper dosimetry byincluding a layer of tantalum, tungsten, titanium, gold, silver, oralloys of these or other high Z materials as a foil, grid or strip,internal to or on a surface of the carrier to facilitate sparing ofnormal tissue by diminishing the penetration of the radiation intoadjacent normal tissues.

Additional embodiments include carriers manufactured as prefabricatedcarriers of various shapes and sizes; and some carriers may be preloaded“hot” with the radioactive seeds or “cold” in order to allow theradioactive seeds to be loaded with specifically desired seeds justprior to an implant procedure.

Further embodiments contemplate carriers which may be configured for theuse of one or more low-energy radioactive seeds selected from Cs 131, Ir192, I 125, Pd 103 or other isotopes used intra-operatively followingsurgical resection to form a permanent implant.

Yet further embodiments may include carriers with short rangeradioisotopes emitting beta or alpha particles.

Another embodiment of a carrier system comprises carrying additionaltherapeutic modalities including chemotherapeutic agents, viraltreatments, targeted therapies, and/or DNA damage repair inhibitors. Thecarriers may further include a semi-permeable or impermeable membrane orother barrier capable of effecting a segregation of this material towardor away from tumor or normal tissues as may be desired.

Additional contemplated features of the carriers may includedifferential color coding to mark seeds with higher radiation strengths,differential thicknesses; indicator lines to allow a user to trim orshape a carrier as needed while maintaining the desired spacing for thecalculated dosimetry; and visual and tactile indicators for a user todifferentiate the tops from bottoms of carriers in the operatingroom/operative field and to maintain correct orientation and desireddosimetry.

A further additional embodiment for the carrier system comprises aatlas/program/spreadsheet/nomogram to guide a user in the planning ofimplants and to assist in ordering seeds/carriers based on preoperativeshape, lesion size, location, histology and number of seeds needed. Suchnomograms might include an atlas of pre-generated pictorial-typedosimetry maps of operative beds by size and shape as a guide to optimalreal-time operative carrier placement and carrier orientation.

Another embodiment comprises a carrier system that is visible on CT andfluoroscopy, and/or is MRI compatible to allow the user to make accurateintra- and post-operative assessments. Additionally, radiofrequencyidentification (RFID) or other remote sensing positioning technology maybe further used for intra and post-operative assessments.

Yet further embodiments of the present invention include inserting theindividual implantable radionuclide carriers into or onto a tumor, avoid remaining following resection, or a tumor bed; to help cure, slowprogression or regrowth, or ameliorate symptoms associated with thetumor.

Additional embodiments of the radionuclide carrier system is forintraoperative permanent brachytherapy in treatment of various tumors ofthe body, including but not limited to tumors of the central nervoussystem, head and neck, soft tissues, bone, spine, lung, breast, skin,esophagus, stomach, liver, intestines, colon, rectum, prostate,pancreas, retroperitoneal space, kidney, bladder, pelvis, ovary, cervix,fallopian tubes, uterus and vagina.

BRIEF DESCRIPTION OF THE DRAWINGS

The principles of the present invention will be apparent with referenceto the following drawings, in which like reference numerals denote likecomponents:

FIG. 1 consists of FIGS. 1A-1F which each show an illustration of dotbased carriers in different configurations.

FIG. 2 consists of FIGS. 2A-2M which each show an illustration of mixeddot based carrier configurations.

FIG. 3 consists of FIGS. 3A-3L which each show an illustration of dotbased carriers in relation to a tumor bed.

FIG. 4 consists of FIG. 4A and FIG. 4B which are illustrations of dotbased carriers attached to a three-dimensional structure wherein FIG. 4Bshows a dime inserted for scale purposes.

FIG. 5 consists of FIGS. 5A-5E which are illustrations of various armbased or star type carriers.

FIG. 6 is an illustration of a arm-based carrier system furtherincluding petal type arms.

FIG. 7 is an illustration of another embodied star or arm based carrier,consisting of FIG. 7A which shows the carrier in an open position, andFIG. 7B which shows the embodied carrier in a closed loading positionwhen attached to an endoscope for loading.

FIG. 8 consists of FIGS. 8A-8D which show an illustration of twoembodied arm based carriers both expanded FIG. 8B and FIG. 8D andcontracted FIG. 8A and FIG. 8C.

FIG. 9 consists of FIGS. 9A and 9B which show an illustration of twomore arm-based carriers in a contracted, FIG. 9A, and expanded position,FIG. 9B.

FIG. 10 is an illustration of another embodied carrier system wherein anarm-based carrier is combined with a plurality of dot based carriers,and fill space in a tumor bed.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based on the real-time selection and use ofrapidly identifiable and conformable radionuclide carriers for providingan optimal dosimetric coverage of a tumor or tumor bed.

Definitions

For the purposes of the present invention Brachytherapy is defined asradiation treatment in which the source of the radiation is placed closeto the surface of the body or within a natural or man-made cavity orspace within the body a short distance from the area being treated.

For the purposes of the present invention Teletherapy is defined asradiation treatment in which the source of the radiation is at adistance from the body.

For the purposes of the present invention High Dose Rate is consideredto be defined as the treatment with radiation doses above 12,000 cGy/hr.

For the purposes of the present invention Low Dose Rate is considered tobe defined as the treatment with radiation in the dose range of 400-2000cGy/hr.

For the purposes of the present invention High Z Materials areconsidered to be defined as any element with an atomic number greaterthan 20, or an alloy containing such materials.

For the purposes of the present invention the term Hot is considered tobe a material that is Radioactive and the term Cold is considered tomean a material is low in radioactivity; or not radioactive.

For the purposes of the present invention Dosimetry is defined as theprocess of measurement and quantitative description of the radiationabsorbed dose (rad) in a tissue or organ.

For the purposes of the present invention Real-time is defined as themoments or minutes during an operative procedure wherein the physiciancan fully visualize and specifically tailor a treatment approach to theexact anatomy and conditions found upon viewing a tumor or aftersurgical resection of a tumor that facilitates an optimal dosimetry in aprecise manner.

For the purposes of the present invention Carrier is defined as abio-compatible device with specific dimensions, both externally andinternally, which functions to contain or carry and position aradioactive source (and possibly additional elements as needed). Thecarrier envisioned, by properties of design and construction, positionsand fixes the location of the radioactive source internal to theindividual carrier and simultaneously facilitates the rapid and precisecombination of multiple carriers to form, when needed, an integratedmulti-carrier structure for the safe and effective treatment of tumors.

For the purposes of the present invention a GammaDot or Dot carrier isdefined as a type of radionuclide carrier that from the top looking downis round or almost round and that when single or multiple dots areplaced in use to treat tumors the dots may surround or be placed withina three-dimensional structure or natural or man-made cavity and thustake on the overall shape of that which they are attached to.

For the purposes of the present invention a GammaStar or arm-basedcarrier is defined as a type of radionuclide carrier that assumes aconformable 3-dimensional shape when arranged and placed into anoperative cavity or similar space and conforms to the treatmentenvironment while maintaining the geometry necessary for an effectiveimplant. However, in some embodiments the GammaStar or arm-based carriermay be used in its initial planar state to cover a relatively flat tumoror tumor bed area.

For the purposes of the present invention the Inverse Square Law appliesto any entity which radiates out from a point in space. The equation is:Intensity=1/distance from the source squared (I=1/d2). With respect toRadiation, the law says if you double your distance from a source ofionizing radiation you will reduce the dose at the new distance by 4. Itfollows that if you reduce your distance from the source by half, itwill increase the exposure to 4× the original value.

For the purposes of the present invention the term Interstitial isdefined as pertaining to parts or interspaces of a tissue.

For the purposes of the present invention the term Operative Bed isdefined as the void left after tissue removal and thus the area in needof treatment to help prevent the re-occurrence of tumors.

For the purposes of the present invention the term Tumor: is defined asan abnormal growth of tissue resulting from uncontrolled, progressivemultiplication of cells; which can be benign or malignant.

For the purposes of the present invention the term Malignant is definedas tumors having the potential for or exhibiting the properties ofanaplasia, invasiveness, and metastasis.

For the purposes of the present invention the term Cancer is defined asany malignant, cellular tumor.

For the purposes of the present invention the term Chemotherapy isdefined as a cancer treatment method that uses chemical agents toinhibit or kill cancer cells.

Application of Embodied Carriers in “Real-Time”

In some applications, such as orthopedics or plastic reconstruction, thepreoperative assessments and intraoperative findings can be verycongruent. In contrast to these settings and despite medical advances,the precise location, exact extent and true configuration of a tumorremains largely unknown until an intra operative procedure. Currentimaging technology is only capable of suggesting tumor vs. other typesof tissue changes, and external imaging is particularly less useful incertain body areas (such as adjacent to highly vascular structures, andat the base of skull) as well as in situations where prior surgery orother treatments have distorted local anatomy. This problem is wellestablished, and many tumor staging systems require the intraoperativeassessment of a tumor as an essential part of the precise evaluation.Adding to and compounding this precise lack of anatomic information isthat the operative bed, i.e. the void left after tissue removal (andthus the area in need of treatment to help prevent the re-occurrence oftumors) is often quite different from the shape and size of theanticipated cavity before the tumor was removed: in addition to the needfor the removed tissue to be greater or smaller than that anticipatedfrom preoperative studies, the nature of the tissues themselves,including elasticity, organ turgor pressure, and the tendency of anyintra-corporeal space created to be rapidly reclaimed by previouslydisplaced adjacent tissues makes a treatment that relies uponpreplanning of precise dose control very difficult to successfullyimplement. Mortality and morbidity increase as operations lengthen, andthe ability to rapidly and precisely adapt to the intraoperativefindings is an essential component of any truly useful implant design.In this setting, real-time refers to moments to minutes, with theability to make any substantive changes which are not just make do, butthat result in optimal solutions in a precise manner which further yieldbetter patient outcomes.

Further embodiments of the radionuclide carrier system, relate to thespecific asymmetrical placement of the radionuclide (seed) in thecarrier which gives the carrier additional inherent properties. Wherein,for example, the normative location of the source is 1) offset away fromthe tumor bed side more than it is from the “normal” tissue side (in a 4mm thick carrier, it is 3 mm off tumor and 1 mm off “normal” tissue).This may be counterintuitive, but in practice is often the best way todo it because a) the normal side is usually a void, and b) if tissuesare nearby, additional spacing material (sheets of collagen, cellulose,etc.) can be interposed. But in some other instances: once sometimeswants a localized dose increase, because either 1) a localized nodule oftumor remains just under one or more carriers, 2) a critical structureexists near or under the implant, such that a localized area ofrelatively lessened dose is desired, 3) that an implant consisting of afew to several carriers uniformly spaced has an inherently lessradioactive periphery and more intensely radioactive center due to theinverse square law (similar to a charcoal grill at the edges and at thecenter), or 3) the implant area is quite small, and just a few carriersin the “normative” position would not deliver an adequate dose. In thesecases the embodied carrier system includes asymmetric source placementof carriers wherein in each case one or more individual carriers arereversed from the normative position (flipped) to solve the problem ofhyper-local dose control. If the usual (normative) orientation isthicker side toward tumor, then flipped is RFNO (‘reversed fromnormative orientation’).

Application of Embodied Carriers in Central Nervous System Tumors

Despite meticulous surgical technique, tumors of the brain or spineoften recur at or near the site of resection. This is because it israrely feasible to resect these tumors with pathologically negativemargins, especially in the more eloquent regions or where lesions areadjacent to vascular structures or nerves. Radiation therapy, utilizingan increasingly large variety of techniques, has been shown to be thesingle most effective adjuvant treatment to help prevent recurrence ofcentral nervous system tumors. Interstitial brachytherapy combined withsurgical resection of central nervous system tumors has been in use forseveral decades. Various types of radioactive sources are inserted underdirect visualization during the surgery, as potentially more costeffective and less time-consuming therapy, without compromisingoutcomes.

Nevertheless, techniques for interstitial brachytherapy (BT) of centralnervous system tumors have remained relatively crude. The brachytherapydevice and methods embodied in the present invention improve thedelivery of radiation by creating a carrier system to createcombinations of carriers, dots and stars, each with radioactive sourcescontained within. These carriers, known as Dot carriers or “GammaDots”and “Star” or “Arm” carriers or “GammaStars” can be positioned to fitinto operative beds by customizing them to the shape and size ofindividual operative cavities. The dots and stars can be tailored toprotect sensitive normal structures, such as nerves or normal brain,while delivering desired high doses of radiation to the preciselocations at highest risk of recurrence. The dots and stars may also beused as carriers for short-range radioisotopes emitting beta or alphaparticles or for delivery of other therapeutic modalities, includingchemotherapeutic agents, viral treatments, targeted therapies, and/orDNA damage repair inhibitors. They may also be designed to contain highZ materials and/or biocompatible spacers to afford significantdirectionality to the radiation treatment.

Application of Embodied Carriers Outside the Central Nervous System

Brachytherapy has been used to treat many tumors of extracranial sitessuch as head and neck, lung, soft tissue, gynecologic, rectum, prostate,penis, esophagus, pancreas and skin. Brachytherapy (BT) can be usedalone or in combination with external beam radiotherapy and/or surgery.Patient outcomes are critically dependent upon proper patient selectionand implantation technique. In general, patients with tumors that areintimately associated with critical normal structures to be preservedsuch as nerves, vessels, cosmetically apparent areas or visceral organscannot be completely resected without undue morbidity or mortality.These tumors may be good candidates for BT performed in conjunction withsurgical resection. Currently available techniques to produce thereliable source spacing needed for optimal geometry and subsequentlyradiation dosimetry, require catheters and shielding that are relativelybulky and therefore poorly conforming to the treated area. Consequently,they require considerable capital investment and the presence of a teamof experts for effective use; and when preformed intraoperatively mustbe undertaken in a specially shielded operating room to avoidirradiation of adjacent staff and patients. These shortcomings limit theavailability of these therapies to very few centers and compromiseoutcomes by decreasing tumor control and increasing complications fromtherapy. The brachytherapy device and methods contemplated in thepresent invention facilitates achieving optimal radioactive sourcearrangements for permanent low dose rate (LDR) BT in a user-friendly,readily available and cost-effective manner, by using a carrier systemof geometrically customizable dot and/or arm-based/star carriers tocontain radioactive sources to be placed into tumors or tumor beds.

Furthermore, the embodiments of the present invention also enables usersto preferentially spare sensitive normal tissue without compromising theability to deliver high dose radiation customized to both tumor andpatient anatomy.

Additional embodiments of the dot and/or star carriers may include theability of the carriers to deliver other cytotoxic agents, such aschemotherapy drugs or very short range radioactive sources such as Y-90and alpha particles for placement directly into tumors, while maximallysparing normal tissue.

Illustrative embodiments of the invention are described below. In theinterest of brevity, not all features of an actual implementation aredescribed in this specification. It will, of course, be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions such as compliance with regulatory,system-related, and business-related constraints, which will vary fromone implementation to another, must be made to achieve the specificgoals. Moreover, such a developmental effort might be complex andtime-consuming but with the benefit of this disclosure, would be aroutine undertaking for those skilled in the art of radiation therapy.

Carrier Systems

Generally the carrier systems described herein and exemplified in FIGS.1-10 involve the utilization of small individual or aggregated,implantable or superficial carriers in the form of dot type carriers (asshown in FIGS. 1-4) and stars or arm-based carrier systems (as shown inFIGS. 5-9) designed to be bearers of therapeutic agents such asradioactive seeds to produce a dosimetrically customizable carriers inreal time for each patient and lesion. Additionally, a combinationcarrier system may include at least one star or arm based carrier incombination with one or more dot type carriers as shown in FIG. 10.

The carrier systems are designed to: create a carrier which allows formore precise and predictable dosimetry; an improved geometry with abetter orientation of seeds to one another especially in the settings ofreal-time, intraoperative environments; is fully customizable to adjustto size/volume, location, and tumor type; and can provide differentialdosing of tumor/tumor bed vs. normal tissues.

The carriers of differential thicknesses and set diameter are selectedin real-time and the carriers may be marked, color coated or observableas having differential thicknesses of seed placement, so if user neededa seed 1 mm from operation bed they would choose a specific dot, ifneeded 2 mm choose a 2 mm specific dot if 3 mm could choose a 3 mmspecific dot or flip a 4 mm thick dot wherein the seed is offset so thatthe seed is 1 mm or 3 mm from the operative bed depending on which sideis towards the operative bed.

The carrier systems embodied are generally made of biocompatiblematerials known in the art and more specifically may be made ofcellulose based or collagen based biocompatible materials.

The dot-based carriers may have different diameters to allow for avariety of spacing and sizing opportunities.

The general star or arm-based carrier designs include arms which aregenerally fixed by height, width and length, and set by need to maintainideal implant geometry of seed spacing. The exact length and widthdepends upon the cavity size but the star carrier itself may be pre madeand/or pre-sized. The arm or star based carrier additionally may haveseed location presets. When the star or arm-based carrier material is inan expanded position or draped position around a three-dimensionalsupport structure the arms and their seed placements offset to maintainseed spacing. The seed spacing contemplated may range from 5 mm to 15mm, with 7.5 mm to 12.5 mm preferred, 8 mm to 12 mm more preferred and10 mm a most preferred seed spacing interval between seeds.

The present invention also may include the use of a small implantableindividual carriers constructed for the localized delivery ofradioactive materials such as gamma or beta irradiation or alphaparticles along with chemotherapy agents ortumoricidal/targeted/immunotherapeutic or viral/viral vector agent(s) onthe side(s) of the carrier(s) adjacent to the tumor.

The present invention also may include the use of a small implantableindividual carrier constructed for the localized delivery of radioactivematerials such as gamma or beta irradiation or alpha particles alongwith radiation sensitizing agents and/or radiation damage repairinhibitors on the side(s) of the carrier(s) adjacent to the tumor.

The present invention also may include the use of a small implantableindividual carrier constructed for the localized delivery of radioactivematerials such as gamma or beta irradiation or alpha particles alongwith radiation protection compounds on the side(s) of the carrier(s)antipodal to the radiation source and/or tissue growth promotion/healingfactor compounds on the side(s) of the carrier(s) antipodal to theradiation source.

The dot or star based carriers in the present invention include theadaptability of the carrier system to be isotope specific and manage theradionuclide strength and exposure to users and normal (non-targeted)tissues with a variety of measures including differential thicknesses asshown above, shielding materials, or spacing facilitators to placeradiolabeled seeds in best place in regards to treatment of target andnon-treatment of non-target.

The carriers may be MRI compatible and/or visible on fluoroscopy,radiofrequency identification (RFID), and CT, to facilitate accurateintra- and post-operative assessment.

The small individual implantable dots and arm or star carriers aredesigned to be carriers for radioactive seeds used to produce adosimetrically customizable implant in real time for each patient andtumor.

The present invention may use a variation of seeds in any carrier (dotor star/arm type carrier) in order to provide the best dosimetry for thepatient, tumor and space. The carriers may include one or more of thesame seeds or various combinations of well-known low energy radioactiveseeds such as Cs 131, Ir 192, I 125, Pd 103 or others commonly known inthe art. The seeds placed within the carriers are generally placed as atherapeutic agent in the form of permanent implants intra-operativelyfollowing surgical resection, but there may be instance where implantsare interchanged removed or replaced.

In other contemplated radionuclide carriers the carrier may include an“up” or “top” designation on the side opposite of the target zonesurface. In instances wherein a dot-based carrier is used, a markingsystem associated with identifying whether the carrier is in thenormative or non-normative position may be present. This marking oridentification system may be done with any indicator, color coding ortextural indicators to alert the user as to what position the carrier isin.

Application and Treatment with Customized Radionuclide Carrier Systems

The specialized carriers of the present invention provide for certainprecise dimensions to allow the carriers to guide users (neurosurgeons,cardiothoracic surgeons, general surgeons, dermatologists, radiationoncologists, urological surgeons, veterinarians or other qualifiedproviders) in maintaining precise and preplanned dosimetry needed toproduce effective and safe outcomes.

The dosimetrically customizable implants of the present invention may beused as a means of treating, curing, ameliorating, or slowing theprogression of various tumors of the body, including but not limited to;tumors of the central nervous system, head and neck, spine, softtissues, bone, liver, lung, breast, skin, esophagus, stomach,intestines, colon, rectum, prostate, pancreas, retroperitoneal space,kidney, bladder, pelvis, ovary, cervix, fallopian tubes, uterus, andvagina.

The embodied carrier systems may be used in methods to facilitateintracavitary, intraluminal, interstitial, and external surfacebrachytherapy used with and without surgical resection of the tumors.

The embodied carrier systems may be used in methods specifically fortreating extracranial, interstitial, intra-cavitary, surface or visceralsite irradiation treatment of various primary and metastatic tumors.

The custom radionuclide carrier systems of the present invention may beused for implantation within the central nervous system and include aradiolabeled implant for interstitial implantation comprising asubstantially rigid implantable matrix design to be a carrier forradioactive seeds to produce a dosimetrically customizable implant inreal-time for each patient and lesion. Additional carrier systemscontemplated are used for superficial or topical treatment of tumorsand/or lesions most often in the skin.

The dosimetrically customizable carriers described herein may be used totreat, cure ameliorate or slow-down the progression and thus provide adefense against various brain tumors including but not limited to,meningioma, glioma, metastatic cancer and craniopharyngioma.

The types of tumors to be treated include primary, secondary andrecurrent tumors involving the central nervous system.

A atlas/program/spreadsheet/nomogram to guide planning implants andordering of seeds and carriers based on preoperative lesion size, shape,location, histology and number may be provided to assist the user whenusing the present carrier systems. A similar program/spreadsheet is alsocontemplated when carriers are not implanted but are applied to a setbody area such as the skin.

This invention would also be useful in veterinary oncology, either aloneor in combination with surgery. Fractionated radiation therapy islogistically more difficult and costly in animals, which requireanesthesia prior to delivery of each fraction. Customizable BT,utilizing this invention, will enable delivery of effective andefficient treatment in properly selected tumors.

Hot-Dot Carrier Embodiments

Some of the general features of the Hot-Dot type carrier are listedbelow:

1) Round or almost round insures easy conformity to flat or curvedsurface.

2) Implant can be constructed quickly using series of round carriers, ofsingle or multiple sizes.

3) Round or nearly round insures stable geometry: just apply with edgestouching, so center to center distance (geometry) is predictable (alwaysdiameter dot a+ diameter dot b/2).

4) When geometry is predictable, dosimetry (radiation dose distributionin tissue) is able to be accurately calculated, either before surgery orintraoperatively.

5) Cold dots of same size can be used as spacers to maintain geometryand avoid too many “hot dots” so lessening chance of uneven dose/hotspots/overdose.

6) Supplied as individual dots, strands of dots, or packs.

7) Trim as needed between dots and trim individual dots to fit.

8) The location of internally placed seed(s) is/are marked on surface soas to allow trimming without disrupting integrity of internal source(s).

9) Biocompatible material, sized from about 5 mm to 20 mm (hot or cold)in diameter and thickness from about 1 to 8 mm, and general 2-5 mm.

FIGS. 1-4 show various exemplifications of carrier devices in dot formembodied in the present invention.

FIGS. 1-3 illustrate the multiple configurations possible with thedot-based system. Additionally, the round design where all of the edgestouch allows and insures equal spacing. “Cold Dots” do not containisotope are used to maintain geometry and/or dosimetry and/or structuralintegrity. Too many “hot dots” can cause too much radiation dose incertain areas, so blanks can be interspersed to lessen the local doseand/or the overall dose as desired.

Additionally, the collection of dots could be preloaded hot or in apattern of hot and cold and excess hot dots could be just punched out asnecessary to insure the correct dosimetry and/or placement is achieved.In FIG. 1 there are strands of “hot dots” which are shown as the dotswith seed indicators. In FIG. 2 “Cold dots” are shown as blank dotswithout a seed indicator line and are used to create the spacing anddosimetry desired.

The embodied carriers are constructed using differential thicknesses ofbiocompatible materials below and/or above the radiation sources (asshown in FIG. 3) to achieve differential radiation dose delivery withrelative sparing of normal tissue along with the use of a layer oftantalum, tungsten, titanium, gold, silver, or alloys of these or otherhigh Z materials on the antipodal aspect (side away from the tumor) orinternal to the carriers to provide sparing of normal tissue in portionsof the body such as the brain and anywhere there is very limitedphysical space.

The present carriers may include the use of differential color codes tomark seeds with higher radiation strength or carrier thickness to tumorbed for improved radiation dose distribution for use with limited sizeand irregular shape targets.

Additional carriers may also have an impermeable membrane, bio-compound,high Z material or other barrier, which acts to prevent or impede themigration of the compound(s) or agents from the side(s) of thecarrier(s) adjacent to the resected tumor to the antipodal side(s) ofthe carrier(s) (adjacent to normal tissue) and vice versa to create adifferential therapeutic impact on the operative bed vs. adjacenttissues.

Additional carriers may use differential thickness of tissue equivalentmaterial below and/or above the dots or stars and/or a construction ofdiffering high Z materials to achieve the desired radiation dosedelivery or normal tissue sparing targeting.

Although single dots may be utilized in the dot-based carrier systems,an advantage of the system is the ability to combine elements (dots) inreal time to deliver a relatively uniform radiation dose to auser-defined area, without having to know or specify ahead of time theexact or near-exact dimensions of the intended treatment area. Priorsystems have not been able to accomplish this degree of specificity in apermanent implant (no need to remove) or not without essentially directcontact of the radioactive sources with the tissue, a situation that canbe extremely injurious. The present embodiments use source(s) within a 3dimensional physical biocompatible carrier(s) of precise dimensions,along with non-source-containing carriers of comparable dimensions andconstruction. This allows the user to combine the elements quickly andeasily in real time to produce the user-specified radiation dosedistributions (dosimetry) desired. Because the location (depth top tobottom) of the source in a carrier is asymmetrical but the otherdimensions are symmetric the carrier can be utilized in either a nominalor reversed (flipped) manner. Either position interposes sufficientmaterial between the source and tissue to prevent directsource-to-tissue contact, thereby lessening the chance of direct tissueinjury by radiation overdose. The Inverse Square Law applies to anyentity which radiates out from a point in space. The equation is:Intensity=1/distance from the source squared (I=1/d2). With respect toRadiation, the law says if you double your distance from a source ofionizing radiation you will reduce the dose at the new distance by 4. Itfollows that if you reduce your distance from the source by half, itwill increase the exposure to 4× the original value.

The nominal position envisioned creates ˜2× the distance to tumor bedthan the reversed/flipped position, resulting in a 94 percent differencein the surface radiation dose between the two orientations. Thisinherent design feature not only allows for a more uniform dose at depththan direct/near direct contact by the source to the treatment area butalso creates a significant ability to manipulate a localized doseincrease (e.g. over a nodule of residual tumor see FIG. 3L) or at theedges of a multi-dot carrier implant where the radiation dose is lowbecause of the inherent physics of radiation (inverse square law). Inaddition, the placement of otherwise dimensionally identical butnon-radioactive dots as spacers allows the user to take advantage ofthese same physics principals to lessen dose to critical structureswithin or near the operative bed, and/or increase the uniformity of theoverall dose within the treatment area. These features, coupled with thestable geometry that round or functionally round carriers enforce whenplaced edge-to-edge allow rapid and predictable radiation dosedistributions to be calculated using standard formulas for almost anyfinal configuration devised.

The dots may be supplied as sheets of sources in biocompatible materialwith concentric circles about each source and marked with 6 mm and 8 mmand 10 mm and 12 mm and 14 mm or similar concentric rings (as FIG. 2F),and punch tool to be used to “cut” these from the sheet as needed in thedesired size(s) and number. These can be “hot” or “cold”, with thelatter to function as spacers in multi-carrier implants.

It is envisioned that the variety of sizes available in the abovecontemplation will facilitate by allowing the user to place sources insmaller or within larger operative areas with greater flexibility.

FIG. 1 consists of FIGS. 1A-1F which provides illustrations ofcontemplated dot based carriers in different configurations. FIG. 1Ashows a dot based carrier 1 with a combination of eight hot dots 2dispersed in two rows of four dot carriers. The seed indicator lines 5in each dot carrier 2 are for illustration purposes only, and are meantto show first that the dot carrier 2 is a hot carrier loaded with aradioactive seed, and that the seed is located near the seed indicatorline 5. FIG. 1B shows the same dot based carrier 1 shown in FIG. 1A froma side view in which the depth of the seed within each dot carrier 2 isindicated with seed indicator lines 5.

FIG. 1C, demonstrates another grouping 101 of dot carriers 2, in thiscarrier grouping 101 there are six rows of hot dot based carriers 2, butthe rows are not uniform in length. The seed indicator lines 5 representthat each dot based carrier 2 is loaded and hot. The carrier systems 101may be further trimmed by removing some of the dots 2 to fit within thetumor or tumor bed 15 (not shown).

FIG. 1D and FIG. 1E, demonstrates two more groupings 201 and 301 of hotdot carriers 2 organized in a symmetrical grouping 201 of seven hot dotcarriers 2 as shown in FIG. 1D or four hot dot 2 carriers shown in thedot grouping 301 of FIG. 1E. Additionally, each dot 2 is indicated ashot based on the seed indicator lines 5 present. The close relationshipof all the hot dots demonstrated by the interconnected seed indicatorline 6 represents a grouping of hot dots to produce a strongradionuclide dose.

FIG. 1F demonstrates another grouping 401 of hot dot carriers 2 thistime in a staggered or asymmetrical grouping 401 of five dot basedcarriers, with seed indicator lines 5 representing the dots as hot.

FIG. 2 consists of FIGS. 2A-2M which each provides an illustration of amixed dot based carrier configuration. FIG. 2A is a single dot 3 basedcarrier but because it does not show a seed indicator line 5, it is ablank or cold dot 3 which are used for spacing and managing thedosimetry demands found in the operative field 15 (not shown). FIG. 2Bis a hot single dot 2 based carrier with a seed indicator line 5. FIG.2C shows a strip 501 of dot based carriers wherein some of the dots arehot 2 and some are cold 3. The dots may be manufactured in strips 501 orin any combination of groupings and trimmed and pieced together at timeof use. FIGS. 2D and 2E demonstrate two more groupings of hot and colddots 601 and 701.

FIG. 2F illustrates a grouping of hot dots 802 formed in a sheet 801with illustrated concentric circles 803 surrounding the seed indicatorline 805 which may be customized at time of use by punching out thedesired sized dots with a punch out tool and placing the different sizedots in accordance with the dosimetric demands of the tumor or tumorbed.

FIG. 2G illustrates the grouping of dot based carriers showing threedifferent doses associated with the dot based carriers, the blank dot 3is once again representative of an unloaded cold dot 3, and the hot dotcarrier 2 with the seed indicator line 5 and otherwise blank isrepresentative of a hot dot 2 in a normative position. The third graydot 4 represents a hot dot such as hot dot 2 but wherein the dot 2 isflipped into a non-normative position 4 resulting in a higherradionuclide dose provided to the tumor or tumor bed.

FIG. 2H represents a top view of another hot dot 8 which additionallyincludes top surface shielding 9 with a high Z material. FIG. 2Iillustrates a side view of the dot 8 of FIG. 2H and shows the relationof the surface shielding 9 compared to the seed location 5.

FIGS. 2J and 2K demonstrate a hot dot carrier 10 that comprises interiorshielding 11 within the dot carrier 10 with a high Z material. FIG. 2Jshows the top view and FIG. 2K illustrates a side view of the dot 10 ofFIG. 2J and shows the relation of the interior shielding 11 compared tothe seed location 5.

FIGS. 2L and 2M demonstrate a hot dot carrier 12 that further comprisesan internal membrane or biologically active material 13 such as a DNAdamage promoter or inhibitor, or a target agent within the dot carrier12. FIG. 2L shows the top view and FIG. 2M illustrates a side view ofthe dot 12 of FIG. 2L and shows the relation of the internal membrane 13compared to the seed location 5.

FIG. 3 consists of FIGS. 3A-3L which each provides an illustration ofdot based carriers in relation to a tumor bed 15. FIG. 3A demonstrates atop view of a cold dot 3, and FIG. 3B illustrates a side view of thecold dot 3 of FIG. 3A placed on a tumor bed 15. FIG. 3C demonstrates atop view of a hot dot 2, and FIG. 3D illustrates a side view of the hotdot 2 of FIG. 3D placed on a tumor bed 15 wherein the respective seedplacement 15 is viewable. FIG. 3E demonstrates a top view of a hot dot 2that has been flipped into the hotter non-normative position 4, and FIG.3F illustrates a side view of the non-normative dot 4 of FIG. 3E placedon a tumor bed 15 wherein the respective seed placement 5 is viewable.

FIG. 3G demonstrates an exemplary grouping of dot based carriers 801placed in an operative or tumor bed 15 which consists of normative 2 andnon-normative 4 placed hot dots and cold dots 3 used as dosimetricspacers. FIG. 3H demonstrates a side view of the third row from the topof the dot based carrier grouping 801 of FIG. 3G wherein each of thedots are cold 3 or hot 4 carriers in their normative position, whereasFIG. 3I demonstrates a side view of the fourth row from the top of thesame carrier 801 and displays the relative seed locations 5 when thedots on the ends are flipped into non-normative positions 4, as comparedto the internal hot 2 and cold dots 3.

FIG. 3J demonstrates another application or grouping of dot basedcarriers in an operative field 15. In this case non-normative hotterdots 4 are found along the periphery of the bed 15 and a grouping ofcold dots 3 is placed around a anatomy to be shielded 15 such as avessel or nerve that is chosen in real-time to not be radiated. If thisvessel or nerve 15 shown were above the implant grouping, the cold dots3 could be replaced by shielded hot dots 9 and still deliver theintended dose to the underlying operative bed (not shown).

FIG. 3K demonstrates another application or grouping of dot basedcarriers in an operative bed 15, but in this case the dots 2, 3, 4 areselected of various sizes and types to fill the field and maintaindosimetric spacing.

FIG. 3L demonstrates yet another application or grouping of dot basedcarriers, in this specific example a grouping of dot carriers areflipped in the non-normative position 4 and thus producing a localized“hotter” area placed over an area of particular concern 19 for tumorregrowth such as a nodule of tissues 19 unable to be surgicallyresected.

FIG. 4 consists of FIG. 4A and FIG. 4B which are illustrations of hotdot 2 based carriers surrounding or draping a three dimensionalstructure 21 and thus taking on the shape of the structure 21 they areattached to. FIG. 4B with the added dime 22 gives a general scale of thedots 2 embodied in the present invention.

Arm-Based or Star Style Carriers Embodiment

FIGS. 5-10 show various exemplifications of carrier devices in star orarm based form embodied in the present invention.

Some of the general features of the Gamma Star type carrier are listedbelow:

1) Design insures easy conformity to spherical or elliptical cavities.

2) Design accommodates symmetrical or asymmetrical cavities.

3) Cavity may have either regular or irregular surface.

4) Cavity may be open ended or closed ended.

5) Pre-loaded Stars (“hot”) or Stars loaded on site (“cold”) conceived.

6) Designed such that implant can be completed quickly using preformedcarriers of adjustable size thereby minimizing radiation exposure tousers and staff.

7) “Size” refers to both a) arm number and b) arm length (see diagrams).

8) Designed with 3-8 “arms”, at intervals of 120 degrees (3 arm starshown in FIG. 5A), 90 degrees (4 arm star shown in FIG. 5B), 72 degrees(5 arm star shown in FIG. 5C), 60 degrees (6 arm star shown in FIG. 5D),51.5 degrees (7 arm star not shown), and 45 degrees (8 arm star shown inFIG. 5E) or similar to achieve desired function.

9) Arm length can be symmetrically shortened (e.g., to fit a smallercavity) and to alter the source number (e.g., thereby altering dose).

10) Arm length can be asymmetrically shortened (e.g. to fit anasymmetrical cavity) and to alter the source number (e.g., therebyaltering dose).

11) Arms can be selectively amputated (e.g., to adapt a 6 arm Star toform a 3 arm star) and to alter the source number (e.g., therebyaltering dose).

12) May be constructed of individual arms, of various lengths, eithersupplied hot or cold.

13) Can be inserted free hand, robotically, endoscopically, or over aballoon-tipped or other expandable catheter.

14) May have an opening or other embodiment at intersection of arms toallow positioning over a catheter or other carrier/introducer.

15) May have additional openings at intervals along the arms to act asan aid in positioning and alignment.

16) May have markings at intervals in standard measures of distance toallow translation of surgical cavity or bed dimensions from directobservation, sounding with probes, ultrasound, CT, MRI or similar to aidin selecting or trimming to the proper size prior to placement. Thesesame openings may act as trim indicators for maintaining a set geometryand thus radiation dosimetry.

17) Radiation source may be sealed isotopic sources (I 125, Pd 103, Cs131, Ir 192, or similar), or another compatible unsealed isotopes (Ra223, Y 90, or similar).

18) Seeds or similar fixed sources would be arranged at set locationsalong the arms consistent with obtaining uniform dosimetric coverage.

19) Temporary or permanent implantation of a biocompatible materialwherein the arm length is from 20 mm to 100 mm; arm width is from 2 mmto 10 mm; and arm thicknesses from about 1 mm to 5 mm.

20) The arms may include a cold “tail” to allow endoscopic or otherplacement and subsequent manipulation or repositioning.

21) Arms may be open or gathered or attached to one another at distalends to facilitate manipulation and placement.

One problem associated surgeons and oncologists often face when treatinga subject include a subject with spherical and semisphericalintracranial lesions which are common and thus so are similarly shapedpostoperative cavities. Any useful carrier and coverage will need toadapt to this shape while being able to be implanted into the brain orother tissues, and still maintain “ideal” or nearly ideal geometry. Onesolution embodied by the present invention includes the creation ofcarriers, that when loaded with seeds and placed in the cavity conformto the three-dimensional environment while maintaining geometry ofimplant. In addition to the three-dimensional nature of the carrier, thecarrier may possess additional possible properties previously mentionedincluding spacing function, differential thickness, and the possibilityof combining with high-z materials for radiation protection. Thesecarriers may also be designed so as to be compatible with placement ofadjacent dots as needed for additional intraoperative flexibility.

Additionally the arm type carrier may be pre-manufactured in specificdimensions and available in a variety of sizes and/or capable of beingtrimmed to make smaller or combined to make bigger at time of use. Thedimensions decided upon can be customized by the user based upon thetumor/cavity size and characteristics to achieve the necessary geometry.

FIG. 5A shows an embodied three arm carrier 7 with spacing 24 of arms 23about 120 degrees away from each other seed indicator lines 25 and cutlines 26 wherein it is safe for the operator to trim the carrier 7without the risk of accidentally releasing or damaging the radioactiveseed (not shown) The carrier 7 also includes a centering hole 27 forassistance when placing the carrier into a tumor bed or operative field15.

FIG. 5B shows an embodied four arm carrier 107 with spacing 24 of arms23 about 90 degrees away from each other and the included seed indicator25, trim lines 26 and centering hole 27 described above.

FIG. 5C shows an embodied five arm carrier 207 with spacing 24 of arms23 about 72 degrees away from each other and the included seed indicator25, trim lines 26 and centering hole 27 described above.

FIG. 5D shows an embodied six arm carrier 307 with spacing 24 of arms 23about 60 degrees away from each other and the included seed indicator25, trim lines 26 and centering hole 27 described above.

FIG. 5E shows an embodied eight arm carrier 407 with the spacing 24 ofthe arms 23 about 45 degrees away from each other and the included seedindicator 25, trim lines 26 and centering hole 27 described above.

FIG. 7A is a drawing of a six arm star carrier 607 that additionallyshows that the arms 23 could be trimmed along trim lines 26 to variablelengths, and the seed placement 25 within the arms may be uniform oralternated depending on the desired dosimetry and geometry required fortreatment. Additionally, the carrier 607 includes a centering hole forplacing the carrier on an introducer 33 and a cold tail end 29 of thearms 23 which allows the user to manipulate the placement of the armsaround the introducer 33 or in the tumor bed 15.

FIG. 7B shows a cross section of the six arm star 607 of FIG. 7Autilizing an endoscope 31 and draping over a unexpanded balloon catheter33 or similar device to introduce the carrier 607 into the tumor bed 15.The arms 23 drape around the catheter 33 radially within the introducerat set distances based on the seed loading placements 25 and the numberof arms 23.

FIG. 8A shows another arm based carrier 707 in the non expanded stateand FIG. 8B shows the carrier 707 in the expanded state. The carrier 707further includes offset seed placements 25 wherein the arms 23 arearound carrier balloons or expanders 34 and the seeds 25 may achieve aspecific geometry in both the unexpanded and expanded positionsadditionally a centering nub 32 mates with the centering hole 27 of thecarrier 707 and helps secure the carrier to the introducer 33, the arms23 may be further manipulated and placed in proper position with the useof the cold tail 29.

FIG. 8C shows another arm based carrier 807 in the non expanded stateand FIG. 8D shows the carrier 807 in the expanded state. The carrier 807further includes matching seed placements 25 wherein the arms 23 arearound carrier balloons or expanders 34 and the seeds 25 may achieve aspecific geometry in both the unexpanded and expanded positionsadditionally a centering nub 32 mates with the centering hole 27 of thecarrier 807 and helps secure the carrier 807 to the introducer 33, thearms 23 may be further manipulated and placed in proper position withthe use of the cold tail 29.

FIG. 9A and FIG. 9B shows comprise of two different arm based carriers907 in FIG. 9A and carrier 1007 in FIG. 9B and demonstrate how anendoscope 33 or similar can be used to place a multi-arm carrier 907 or1007 and the seeds 25 will maintain distances based on their placementson the individual arms 23.

The proportions are generally fixed by height, width and length, and setby need to maintain ideal implant geometry of seed spacing. The exactlength and width depends upon the cavity size but the arm-based carrieritself may be pre made and/or pre-sized. The star or arm-based carriersadditionally may have seed location presets.

The carriers of the present invention may also provide for the use of asmall implantable individual carrier constructed for the localizeddelivery of radioactive materials such as gamma or beta irradiation oralpha particles along with radiation sensitizing agents and/or radiationdamage repair inhibitors on the side(s) of the carrier(s) adjacent tothe tumor.

The carriers of the present invention may also provide for the use of asmall implantable individual carrier constructed for the localizeddelivery of radioactive materials such as gamma or beta irradiation oralpha particles with or without other radiation protection compounds onthe side(s) of the carrier(s) antipodal to the radiation source and/ortissue growth promotion/healing factor compounds on the side(s) of thecarrier(s) antipodal to the radiation source.

The carriers may also have differential thicknesses of the carriersthemselves, wherein the carriers may range from about 2 to 6 mm thick.The seed placement in carriers of differing thicknesses may cover arange of depths for both normative placement distances and non-normativeplacement distances. For instance a 5 mm thick carrier may have anormative distance at 3 mm and a non-normative distance of 2 mm. If onewere to have a 4 mm thick carrier with a 3 mm normative distance and 1mm non-normative distance and another 4 mm thick carrier with a 2.5 mmnormative distance and a non-normative distance, one can easily andrapidly have seed distances ranging from 1, 1.5 2, 2.5 and 3 mm just byhaving three different carriers ready. It is also possible to expandthis range further with thicker carriers.

Stars: Problems to be solved: 1) Uniform surface dose distributions forcavities, where known dimension is a linear diameter; 2) maintainingposition of sources in a uniform geometry and predictable manner once an“optimal” distribution determination is made; 3) placement withincavity/void with a minimum of additional tissue manipulation (esp. as itrelates to small areas); 4) potential for adaptability tonon-uniform/partially asymmetric cavities/voids; 5) rapidity of process.

GammaStars: Table 1 (all distance measurements in cm or cm2) SurfaceDiameter Area # Sources Arm Length # Sources/arm #Arms 1.00 3.1 3 1.6 13 1.25 4.9 4 1.9 1 4 1.5 7.1 6 2.25 2 3 1.75 9.6 9 2.75 3 3 1.75 9.6 82.75 2 4 2.0 12.6 15 3.1 3 5 2.0 12.6 12 3.1 3 4 2.25 15.9 15 3.5 3 52.5 19.6 20 3.9 4 5 2.75 23.8 24 4.3 4 6 3.0 28.3 24 4.7 4 6 3.0 28.3 304.7 5 6 3.25 33.2 30 5.1 5 6 3.5 38.5 36 5.5 6 6 3.5 38.5 35 5.5 5 73.75 44.2 42 5.9 7 7 3.75 44.2 40 5.9 5 8 4.0 50.3 48 6.3 6 8 4.0 50.349 6.3 7 7 4.25 56.7 56 6.7 7 8 4.5 63.6 64 7.0 8 8 4.75 70.9 64 7.5 8 85.0 78.5 72 7.8 9 8

Table 1, column 1: lists diameters of some commonly encountered surgicalcavities.

Table 1, column 2: relates diameter of sphere to surface area of sphereof this diameter (4piR2).

Table 1, column 3: relates surface area to the number of sources needed,assuming 1 source per cm2 of surface area.

Table 1, column 4: relates possible star “arm” length for given cavity(circumference/2).

Table 1, column 5: relates possible number of sources per arm, at aspacing of ˜1 per linear cm.

Table 1, column 6: relates possible number(s) of arms on a star that areneeded to treat surface area from column 2 at ˜1 source/cm2 of surfacearea with a uniform geometry.

Star Selection Process:

1) Determine cavity/void diameter (Sound, ultrasound, CT, MRI orvisually) (Table 1, column 1)

2) From diameter, determine surface area in cm2 (Table 1, column 2)

3) Using ˜1 source per cm2 area, determine the number of sources needed(Table 1, column 3)

4) Star selection (how many arms) (Table 1, column 4) is made on thenumber of sources needed overall, with the approximation of 1 source percm along radial length of arm Table 1, column 5 and column 6) for agiven diameter. As shown in Table 1, column 3 sometimes multiplecombinations result and would be similarly efficacious.

Star insertion Process:

A) Over Guide:

1) Choose star as above 2) slide star over guide with tip of guide incentering hole/depression at closed end of star (intersection of arms)3) insert to desired position in cavity/void, trimming arm or arm excessas needed 4) withdraw guide 5) position, pack open, suture, glue orotherwise secure star to side of cavity/void.

B) Over Expandable Catheter:

1) Choose star as above 2) position Star over appropriate catheter withcentering tip (FIG. 3 new) such that tip end of catheter extends toclosed end of Star and cold tail is just beyond the expansion area ofcatheter 3) insert to desired position in cavity/void, trimming arm orarms as needed 4) expand catheter to desired characteristics 5) collapsecatheter 6) withdraw catheter 7) position, pack open, suture, glue orotherwise secure star to side of cavity/void.

C) Via Endoscope or Similar with Expanding Catheter:

1) Choose star as above 2) position Star over appropriate catheter withcentering tip such that tip end of catheter extends to closed end ofStar and cold tail is just beyond the expansion area of catheter (FIG. 4new) 3) insert to desired position in endoscope or introducer, trimmingarm or arms as needed 4) insert endoscope or introducer to desiredposition in cavity/void 5) withdraw endoscope or further catheter withcentering tip such that in either case the catheter introducer/starapparatus is in desired location and cold tail remains within endoscope6) expand catheter to desired characteristics 7) collapse catheter 8)withdraw catheter 9) position, pack open, suture, glue or otherwisesecure star to side of cavity/void 10) withdraw endoscope. It isrecognized that variations in this technique are likely to arise.

Arm-Based Flower Petal Style Carrier Embodiment

FIG. 6 shows an embodied arm based carrier 507, wherein the petal arms28 are thicker and more like petal structures than the arms 23 of thecarriers shown in FIG. 5. The broader petal arms 28 embodied in thePetal style carrier 507 allow for greater spacing control betweencarrier arms 28 and structural support. Additionally, the petal stylearms 28 may be constructed to facilitate the localized delivery ofradioactive materials such as gamma or beta irradiation or alphaparticles along with chemotherapy agents ortumoricidal/targeted/immunotherapeutic, viral/viral vector agent(s),radiation sensitizing agents and/or radiation damage repair inhibitors;on the side(s) of the carrier(s) adjacent to the tumor and/or radiationprotection compounds on the side(s) of the carrier(s) antipodal to theradiation source and/or tissue growth promotion/healing factor compoundson the side(s) of the carrier(s) antipodal to the radiation source.

The petal based carrier 507 of FIG. 6 can be customized along thevarious trim lines 26, or have arms 28 removed based on the limitationsof the operative field. The petal based carrier also includes seedindicator lines 25 and a centering hole 27 for assistance when placing.

Combination of Dots and Arm-Based or Star Style Carriers Embodiment

As shown in FIG. 10 it is possible to combine an arm based carrier 907and a plurality of different dot sized carriers 2 to create a carriersystem for filling a tumor bed and maintaining a precise dosimetry. Thecombination carrier system may be placed with an introducer or catheter33 into a tumor bed or operative field 15. The arms 23 of the arm basedcarrier 907 have space between which is filled with hot dot carrier 2 ofdifferent sizes.

Although the invention has been described with reference to the aboveexamples, it will be understood that modifications and variations areencompassed within the spirit and scope of the invention. Accordingly,the invention is limited only by the following claims.

What is claimed is:
 1. A treatment system comprising: an introducercomprising a mating tip sized to engage with a radioactive seed carrierto maintain position of the radioactive seed carrier with reference tothe introducer as the radioactive seed carrier is inserted into a cavityof a mammal, wherein the introducer is removable from the radioactiveseed carrier; the radioactive seed carrier comprising: a central portionhaving an aperture configured to receive the mating tip of theintroducer; a plurality of elongate members each having: a proximal endcoupled to the central portion; a distal end; and a carrier portionbetween the proximal end and the distal end, the carrier portionembedding one or more radioactive seeds in a spaced relationship;wherein the radioactive seed carrier comprises a collapsed state whereineach of the plurality of elongate members are substantially parallel toone another about a central elongate axis between the plurality ofelongate members; and an expanded state wherein each of the plurality ofelongate members are flexed outward from the central elongate axis abouta central portion of respective elongate members; wherein the introduceris adapted for removal from the radioactive seed carrier.
 2. Thetreatment system of claim 1, wherein the introducer comprises a catheterhaving a balloon adapted for insertion into the cavity of a mammal towhich radioactive therapy is prescribed, wherein the balloon has aninflated state wherein volume of the balloon is greater than in adeflated state, the balloon being adapted for placement in the cavity ofthe mammal in the deflated state and inflation to the inflated statewhen in the cavity.
 3. The treatment system of claim 1, wherein theradioactive seed carrier is adapted to retain the expanded state withinthe cavity of the mammal after the introducer is removed from within theradioactive seed carrier.
 4. The treatment system of claim 1, whereinthe introducer comprises an endoscope.
 5. A method comprising:determining a carrier configuration based on a radiation therapy plan,the carrier configuration indicating at least: an arm quantity ofelongate arms, the arm quantity being at least three; and a seedquantity of radioactive seeds for each of the elongate arms, the seedquantity being at least one; preparing a radioactive seed carrier havinga plurality of elongate arms and a plurality of radioactive seedsmatching the determined carrier configuration embedded therein; engaginga mating tip of an introduction device with a mating aperture of theradioactive seed carrier; with the introduction device mated to theradioactive seed carrier, moving the introduction device so that theradioactive seed carrier is within a cavity of a mammal; and withdrawingthe introduction device, leaving the radioactive seed carrier within thecavity of the mammal.
 6. The method of claim 5, further comprising:trimming a first elongate arm of the plurality of elongate arms toshorten length of the first elongate arm.
 7. The method of claim 6,wherein the first elongate arm includes one or more visible trim linesidentifying portions of the first elongate arm where no radioactiveseeds are embedded.
 8. A method comprising: positioning a radioactiveseed carrier for engagement with an introduction device, the radioactiveseed carrier having a plurality of elongate arms, each of the pluralityof elongate arms having one or more radioactive seeds embedded therein;engaging a mating tip of the introduction device with a mating apertureof the radioactive seed carrier; moving the introduction device toinsert the radioactive seed carrier within a cavity of a mammal; andwithdrawing the introduction device, leaving the radioactive seedcarrier within the cavity of the mammal.
 9. The method of claim 8,further comprising: causing a portion of the introduction device withinthe radioactive seed carrier to expand, thereby expanding at least someof the elongate arms within the cavity of the mammal.
 10. The method ofclaim 8, further comprising: receiving, from a provider, the radioactiveseed carrier with radioactive seeds embedded therein.
 11. The method ofclaim 8, further comprising: determining a quantity of elongate arms,the arm quantity being at least three; and preparing the radioactiveseed carrier, wherein the plurality of elongate arms is the determinedquantity.